1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor laser element used for optical communication, for example.
2. Background Art
Japanese Patent Application Laid-Open No. 64-73726 discloses a technique for detecting an etching end point through an etching end point detection layer formed beforehand when etching an object to be processed.
In dry etching, ridge etching that forms a ridge of a semiconductor laser element involves a problem that a stable etching depth cannot be achieved due to a variation in capability of an etching apparatus. When a ridge height is not stable, a problem may occur that a leak path is formed in a current block layer in which the ridge is embedded.
An etching end point detection layer may be used to make an etching depth stable. However, since the method described in Japanese Patent Application Laid-Open No.64-73726 forms an etching end point detection layer on the entire surface of a substrate, the etching end point detection layer exists in the current path of the semiconductor laser element. In this case, carriers may be trapped at a level of the etching end point detection layer, resulting in a problem of adversely affecting characteristics of the semiconductor laser element.